In a large bowl, mix the grated onion and its juices, breadcrumbs, egg, kosher salt, and black pepper until combined.
Add the ground beef and mix well (hands work best).
Divide into 4 portions and form oval-shaped patties about 3/4 inch thick.
Cook the Steaks:
Heat a large skillet over high heat. Once hot (about 2 minutes), add olive oil.
Sear patties 2 minutes per side until browned. Remove to a plate.
Make the Mushroom Gravy:
Melt butter in the skillet. Add mushrooms and cook 2 minutes until golden.
Sprinkle flour over mushrooms, stir to coat, and cook 1 more minute.
Gradually add beef broth, stirring constantly, and bring to a simmer.
Return patties to the skillet and simmer uncovered for 5 minutes until fully cooked and gravy thickens.
Optional: Garlic Mashed Potatoes
Boil potatoes until tender, about 15 minutes. Drain.
Mash with butter, milk, garlic, salt, and pepper until smooth and creamy.
Serving & Storage Tips
